Analytical modeling of composite manufacturing by vacuum assisted infusion with minimal experimental characterization of random fabrics

A new analytical formulation of governing equations for hydro-mechanical coupled problem during single sided molding processes such as vacuum infusion (VI) is presented in this study. The main complexities of VI modeling are the non-linear pressure profile and thickness evolution during filling. The research is focused on the relationship between flow progression, pressure changes and thickness distribution inside the cavity during infusion process. Solution of a moving boundary problem in terms of resin flow front position and pressure distribution is derived without the need for an explicit empirical law for permeability decrease with fiber volume fraction, neither for the fibers preform mechanical compressive behavior. In order to predict the thickness distribution over time, only permeability change with preform thickness is now required. The proposed model is derived and validated with experimental data where random fabric was considered. Better prediction for flow front position, pressure profile along flow length, and thickness distribution over time is obtained compared to other models found in the literature. A new characteristical parameter on fiber reinforcement linking preform thickness, permeability and flow front position is presented and validated with experimental data. An accurate model for infusion process with reduced material data inputs has thus been achieved.